Stratified entomological sampling in preparation for an area-wide integrated pest management program: The example of Glossina palpalis gambiensis (Diptera: Glossinidae) in the Niayes of Senegal

The riverine tsetse species Glossina palpalis gambiensis Vanderplank 1949 (Diptera: Glossinidae) inhabits riparian forests along river systems in West Africa. The government of Senegal has embarked on a project to eliminate this tsetse species, and African animal trypanosomoses, from the Niayes area usinganarea-wideintegrated pestmanagementapproach.AstratiÞedentomologicalsamplingstrategy was therefore developed using spatial analytical tools and mathematical modeling. A preliminary phytosociological census identiÞed eight types of suitable habitat, which could be discriminated from LandSat 7ETM_satellite images and denominated wet areas. At the end of March 2009, 683 unbaited Vavoua traps had been deployed, and the observed infested area in the Niayes was 525 km2. In the remaining area, a mathematical model was used to assess the risk that ßies were present despite a sequence of zero catches. Theanalysisshowedthat this riskwasabove0.05 in19%of this area that willbeconsideredas infestedduring the control operations. The remote sensing analysis that identiÞed the wet areas allowed a restriction of the area to be surveyed to 4% of the total surface area (7,150 km2), whereas the mathematical model provided an efÞcient method to improve the accuracy and the robustness of the sampling protocol. The Þnal size of the control area will be decided basedonthe entomological collection data. This entomological sampling procedure might be used for other vector or pest control scenarios.